1. Field of the Invention
The present invention relates to improving color matching accuracy when recording N types of ink drops containing different amounts of ink onto a printing medium, under to a plurality of printing conditions.
2. Description of the Related Art
In printing devices, even where images are printed on the basis of a given set of image data, printing can typically be executed under different multiple printing conditions by means of selecting the resolution and so on. Where printing conditions differ, various conditions besides the resolution mentioned above, such as the amount of ink per single ink drop, will vary as well; this makes it necessary to perform color matching, so that images printed on the basis of given image data in a printing device will always have the same color. In the past, color matching has been performed by creating a color conversion table for each resolution, and selecting a color conversion table to match the resolution at the time of printing (see, for example, Unexamined Patent Application 9-186898).
In printing control devices of this type, making reference to a color conversion LUT (color conversion table), image data consisting of RGB (red, green blue) tone values is color-converted to image data consisting of CMYK (cyan, magenta, yellow, black) one values for example; dot recording rates for dots of each size producible by the printer are determined; dot on-off state for each dot size is decided on the basis of the determined dot recording rates; and dots are formed by the printer on the basis of the decision results. In the printer, dots corresponding to given decision results are formed on a printing medium, to print a multi-tone image (see Unexamined Patent Application 2001-158085). With this same technology, for each dot size, selection patterns that combine CMY dots are printed onto a printing medium, the selection pattern visually determined to have the best CMY balance due to variability in ink ejection quantity is selected, and on the basis of the result, the recording level specifying data is corrected in such a way as to compensate for shift in CMY balance. Then, referring to the corrected recording level specifying data, dot on-off state for each dot size is decided, and dots are formed on the basis of the decision results.